Vet Column 11-16-09 |

Vet Column 11-16-09

David L. Morris, DVM, Ph.D.
Fort Collins, Colo.

Backgrounding, the time period between weaning and finishing cattle, is used to prepare cattle for finishing programs. Backgrounding can be a tool to improve uniformity in cattle body weight and composition. Backgrounding systems typically involve feeding cattle for moderate growth, allowing for maturation of muscle and bone while restricting fat deposition. This opportunity for body development before finishing allows cattle to attain greater carcass weights at harvest.

Backgrounding can sometimes be justified for economic and other reasons. Backgrounding can include utilizing homegrown feeds, take advantage of grazing opportunities, delaying finishing to target a specific market, acclimate calves to eating from bunks and drinking from a fountain waterer, or promoting skeletal growth of small-framed cattle.

Previous studies have demonstrated that nutrition and management practices, including differing breed types, during the backgrounding phase are major contributors to finishing performance and carcass characteristics. Investigators from North Dakota State University and the University of Nebraska recently examined the effects of backgrounding rate of gain on subsequent feedlot performance, carcass characteristics, Warner-Bratzler shear force, and sensory analysis.

Eighty steer calves (76 Angus-sired and four were Angus-Simmental sired) from predominantly Angus cows were used to evaluate the effects of two different rates of body weight gain (eight calves per pen; five pens per treatment) and its effects on growth performance and calf health during the backgrounding period. The steers in this study averaged 505 pounds with a low of 428 pounds to a high of 575 pounds. Average age was six and a half months. All steers were provided a diet adaption period of 14 days. The backgrounding period was 70 days.

The low gain diet was designed for 2.0 pounds per day and the high gain diet was formulated for 2.75 pounds per day average daily gain. The low gain ration included 52.5 percent barley silage, 39.0 percent whole shell corn, and 8.5 percent supplement. The high gain ration included 43.9 percent barley silage, 47.4 percent whole shell corn, and 8.7 percent supplement, both rations based upon dry matter basis. After backgrounding, steers were fed the same finishing ration for 135 days. Finishing endpoint was determined when one-third of all calves measured 0.45 inches of backfat at the 12th rib by ultrasonic evaluation.

Results indicate that backgrounded steers in the high gain group grew faster (3.7 pounds per day average daily gain) than the low gain group (3.1 pounds per day average daily gain). During the finishing period, however, no differences in average daily gain occurred. Both groups averaged 3.4 pounds per day gain. Dry matter intake during the finishing period was not different for either treatment group.

Hot carcass weight, marbling score, 12th-rib fat, loin muscle area, and USDA yield grade were not different for either the low gain or high gain backgrounded groups. Both groups averaged low choice quality grade at harvest. Tenderness of rib-eye steaks from both groups was equal. Consumer sensory analysis of tenderness, juiciness, and flavor intensity were equal as well among both treatment groups.

These data suggest that feeding steers backgrounding diets that differ in energy concentration resulting in average daily gains of 3.1 and 3.75 pounds per day for 70 days results in minimal changes in subsequent finishing performance and does not affect meat quality. This study did not evaluate potential differences of smaller or larger average daily gains during the backgrounding period.

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